Paving machines may incorporate a paving kit, dowel bar inserter, texturing device, or other attachments and accessories secured to a framework that extends laterally across the roadway or surface being paved, generally perpendicular to the direction the machine travels during paving or texturing operations. The framework may be a modular framework incorporating multiple frame members which can be inserted or removed to quickly reconfigure the paving machine. The framework may support a diesel engine, electrical generator or other like power unit for propelling the machine or supplying power to accessories and components, and is generally supported at either end by an end car (ex.—end structure). Each end structure may in turn incorporate a leg (ex.—vertical support) at either end. For example, a four-track machine may include two end cars, one at either end of the main framework, and four legs, each end car having a leg connected at its front and rear.
Each leg may be connected to a steerable crawler which contacts the ground via a crawler track. The steerable crawlers may rotate via manual, hydraulic, electronic over hydraulic, or other like means of actuation in various combinations so that the paving machine may be steered while in operation or reconfigured to minimize the machine's width for safe transport along a road or highway. The steerable crawlers may be actuated in combinations depending on the desired steering mode. For example, a four-track machine may steer in front or rear steering mode, where both front or rear steerable crawlers turn in unison. In a coordinated steering mode, the two front crawlers may turn in a single direction and the two rear crawlers in the opposite direction to minimize turn radius. In a crab steering mode, all four crawlers may turn in unison to more easily orient the machine on line or position the machine on another vehicle for transport. In a rotation mode, the steerable crawlers may be positioned to allow the machine to rotate through a full 360 degrees within its own dimensions; for example, each opposing pair of crawlers may be rotated so that each crawler steers in the opposite direction from its opposing companion crawler (left front/right rear, right front/left rear). Alternatively, the vertical support and steerable crawler may be connected to an end structure through a pivot arm or leg capable of rotation around an axis defined by the point of connection. Each end structure may incorporate a pair of pivot arms (i.e., one connected to the front and rear legs), each of which couples the end structure a leg (and a steerable crawler connected thereto) and may additionally articulate the leg through a combination of actuators, turnbuckles, or other like devices.
A potential problem with this configuration occurs when the machine is converted from an operational configuration to a transport configuration that minimizes overall width. Generally, in an operational configuration all four steerable crawlers of a four-track machine will be oriented in the direction of the paving or texturing operation (i.e., perpendicular to the lateral framework of the machine) and in a transport configuration all four crawlers will be oriented in the direction of the lateral framework (i.e., rotated 90 degrees from an operational configuration) to minimize the overall width of the machine. In machines incorporating pivot arms to connect an end structure to vertical supports (ex.—legs), extension of the pivot arms beyond the plane defined by the outer edge of the end structure may require the hydraulic actuators or turnbuckles securing the pivot arms to the main framework or end structure to be repositioned or disconnected. This disconnection (and subsequent reconnection) can be a time consuming process, especially if the pivot arms, associated legs, and connected steerable tracks must then be rotated manually to a new position. It may therefore be desirable for a pivot arm assembly to allow greater flexibility of reconfiguration without the need to manually disconnect or reposition components.